This invention relates to a thermal motor with mechanism for converting the motor piston stroke to a selected longer stroke. The thermally actuated motor may be of the type shown in U.S. Pat. No. 3,029,595 granted to John F. Sherwood, and other patents assigned to the assignee of this application, in which the expansion of wax is utilized as the means for actuating the motor shaft. Thermal motors of the kind disclosed in prior art patents have a relatively short piston stroke, such as approximately 11/16 inch.